.. _examples:

Usage Examples
==============

This page documents several simple use cases for you to try out.
For full details, see the :ref:`reference`, and check out the full
class reference for :class:`.RobotModel`.

Loading from a File
-------------------

You can load a URDF from any ``.urdf`` file, as long as you fix the links
to be relative or absolute links rather than ROS resource URLs.

>>> import skrobot
>>> robot_model = skrobot.models.urdf.RobotModelFromURDF(urdf_file=skrobot.data.pr2_urdfpath())


Visualization
-------------

>>> viewer = skrobot.viewers.TrimeshSceneViewer(resolution=(640, 480))
>>> viewer.add(robot_model)
>>> viewer.show()

If you would like to update renderer:

>>> viewer.redraw()

Accessing Links and Joints
--------------------------

You have direct access to link and joint information.

>>> for link in robot_model.link_list:
...    print(link.name)


>>> for joint in robot_model.joint_list:
...     print(joint.name)


>>> robot_model.l_elbow_flex_joint.joint_angle()
0.0

>>> robot_model.l_elbow_flex_joint.joint_angle(-0.5)
-0.5

>>> robot_model.l_elbow_flex_joint.joint_angle()
-0.5

Inverse Kinematics
------------------

This section provides a basic example of inverse kinematics. For comprehensive documentation 
including axis constraints, batch processing, and advanced features, see :doc:`../reference/robot_model_tips`.

First, set the initial pose. Note that the position of the prismatic joint is in [m] and angles of rotational joints are in [rad].

>>> robot_model.torso_lift_joint.joint_angle(0.05)
>>> robot_model.l_shoulder_pan_joint.joint_angle(60 * 3.14/180.0)
>>> robot_model.l_shoulder_lift_joint.joint_angle(74 * 3.14/180.0)
>>> robot_model.l_upper_arm_roll_joint.joint_angle(70* 3.14/180.0)
>>> robot_model.l_elbow_flex_joint.joint_angle(-120 * 3.14/180.0)
>>> robot_model.l_forearm_roll_joint.joint_angle(20 * 3.14/180.0)
>>> robot_model.l_wrist_flex_joint.joint_angle(-30 * 3.14/180.0)
>>> robot_model.l_wrist_roll_joint.joint_angle(180 * 3.14/180.0)
>>> robot_model.r_shoulder_pan_joint.joint_angle(-60 * 3.14/180.0)
>>> robot_model.r_shoulder_lift_joint.joint_angle(74 * 3.14/180.0)
>>> robot_model.r_upper_arm_roll_joint.joint_angle(-70 * 3.14/180.0)
>>> robot_model.r_elbow_flex_joint.joint_angle(-120 * 3.14/180.0)
>>> robot_model.r_forearm_roll_joint.joint_angle(-20 * 3.14/180.0)
>>> robot_model.r_wrist_flex_joint.joint_angle(-30 * 3.14/180.0)
>>> robot_model.r_wrist_roll_joint.joint_angle(180 * 3.14/180.0)
>>> robot_model.head_pan_joint.joint_angle(0)
>>> robot_model.head_tilt_joint.joint_angle(0)

Next, set move_target and link_list

>>> rarm_end_coords = skrobot.coordinates.CascadedCoords(
...             parent=robot_model.r_gripper_tool_frame,
...             name='rarm_end_coords')
>>> move_target = rarm_end_coords
>>> link_list = [
...     robot_model.r_shoulder_pan_link,
...     robot_model.r_shoulder_lift_link,
...     robot_model.r_upper_arm_roll_link,
...     robot_model.r_elbow_flex_link,
...     robot_model.r_forearm_roll_link,
...     robot_model.r_wrist_flex_link,
...     robot_model.r_wrist_roll_link]

Set target_coords.

>>> target_coords = skrobot.coordinates.Coordinates([0.5, -0.3, 0.7], [0, 0, 0])
>>> robot_model.inverse_kinematics(
...     target_coords,
...     link_list=link_list,
...     move_target=move_target)

For detailed information about inverse kinematics including:

- Axis constraints (``rotation_axis`` and ``translation_axis`` parameters)
- Batch inverse kinematics for multiple poses
- Visual examples of different constraint types
- Advanced features and performance optimization
- Common usage patterns

See the comprehensive :doc:`../reference/robot_model_tips` documentation.